The last few times out when the problem showed up it was reading 13.5. It fluctuates a lot when driving but I've tried to get a quick read from the display each time. My son suggested that I set up the GoPro so that it records the screen as I'm driving and with me narrating a live report of engine behavior. I haven't seen any major changes in the readouts when I've looked but I am keeping my eyes on the road at the same time. It's possible that there could be a trend that I haven't noticed.